1. Field of the Invention
The field of art to which this invention relates is a fuser stripper apparatus for use in machines such as printers, facsimile machines, photocopiers, and the like, for preventing sheets and envelopes fed into the machine from wrapping around a fuser roller.
2. Description of the Related Art
In machines in which an image is imparted from a fuser roller to a sheet of paper or an envelope or the like, a common problem is preventing the paper from wrapping around the fuser roller and becoming jammed in the machine. Paper jams result in machine downtime and possibly, expensive maintenance. Additionally such a fuser roller is typically heated which adds to the wrap-around problem previously mentioned in that paper is more prone to curl when heated, especially treated paper or waxed paper having labels affixed thereto.
Stripper devices of the prior art attempt to solve the wrap around problem with fingers, claws, or pawls which are spring loaded toward a surface of the fuser roller to prevent paper fed thereto from wrapping around the fuser roller. While other stripper devices of the prior art use scraper blades urged against the fuser roller to prevent papers fed thereto from wrapping around the fuser roller.
While the prior art stripper devices are somewhat useful, they all suffer from the same disadvantages; they are generally complicated and expensive to fabricate. These stripper devices can also affect the quality of the reproduction because they are in rubbing contact with the surface of the fuser roller. More importantly, the stripper devices of the prior art are not foolproof. That is, as is commonly known, paper, envelopes, and sheets of labels still manage to get between the prior art stripper devices and the surface of the fuser roller to become jammed.
The problem with the prior art stripper devices is inherent in the way the prior art addresses the problem, namely, something is biased towards the surface of the fuser roller, typically with a spring. However, if the paper being fed over the fuser roller has a sufficient force to lift the device from the fuser roller surface, the device's effectiveness is lost. Of course, a spring having a great enough spring force can be used which would make it unlikely to be lifted away from the surface of the fuser roller. However, such a spring force would affect the rotation of the fuser roller, requiring greater torque to rotate it. Furthermore, such a force urging a stripper device against the fuser roller surface would certainly affect the ability of the fuser roller to impart the proper amount and pattern of toner in the area which contacts the stripper device and may even damage the coating on the fuser roller surface.
For these reasons a fuser stripper apparatus is needed which is simple, economical, does not affect a rubbing contact with the fuser roller and which substantially eliminates the possibility of paper jams from occurring due to wrap-around of the fuser roller.